Improvement in piston-valyes foe steam-hammers



@uitrit faire gat-ritt @ritira f DAVID univr, OESHEFFIELDQTENGLAND.

'Lttersldatent o. 'i8..933. dated June 16.1 1868.

'IMPROVEMENT VlhlfPlSlOhl-VLAIN'I''SI FOR STEAM-HAMMERS.

TO ALL WH'OM IT 'MAY CONCERN: y i

Be it known that I, DAVID DVY, of Sheffield, in the county of York, England, have invented a new and useful Improvement in Steam-Hammers and I do hereby declare that the following isa full, clear, and exact description thereof, which will enable others skilled in the art to make and use the same, reference heinghad to the accompanying drawings, forming a part oi' this specification.

The'objectof this invention is to provide means for economizing'steam in the use of` steam-hammersTor of hammers actuated by any other` elastic iluid, when such hammers are working with a varying length of stroke. The Acylinder and piston to which the hammer is immediately' connected, may be constructed in anyv of the various forms usually' adopted, but the distribution of steam or other, iuid is effected as follows:

` Ipropose using a'pistpn-valve, with two ,or more pistons or valves upon the rodhbut for, the-present purpose I will describe the one with two'pistons or valves. i

The steam or other duid is admitted into the valve-chest between the two pistons, and the exhaust steam passes into the valve-chest fromthe-A'cylinder at each end iot' -the valves-heet, and from thence into the'exhauslt-pipe.

The pistons or valves are hollow, and around their circumference are'por'ts corresponding with and opposite, or nearly so,with` other ports in the valve-casing.

By this means when the valves or pistonsare in a c the top-and bottom of thecylinder.

The valves are made to reciprocate in the casing either by hand or by a self-,acting motion.'

The ports in the valve-casing answer both for'the ingress and egress ci' the steam, and for passing it from the top to the hottom of the hammer-cylinder, lor vice versa, but the ports around the circumference of the pistonvalves, and the passageconnecting them together, are only used as a communication for equalizing the pressure of the steam in the top and bottom of the hammer-cylinder. m

The mode of operation is as follows Supposing the hammer is to be raised as for commencing operations, une valves will be movedin a downward direction, admitting the steam or other iiuid to the underl side of the piston, and when the piston has ascended suilciently high, the valves will be moved inl an opposite direction, till the equilibrium-ports in the valve are opposite the ports in the casing. i

In this position a portion of 'the steam or other fluid which has raised the hammer will pass fromthe lower to the 'upper-,side of `the piston, thereby equalizing the pressure on both sides of the piston, when the hammer will descend 'with a velocity due to gravitation alone. l When it has descended, the valves will be again reversed, the equilibrium-ports will be closed, and the steam or other fluid ontthe under side of the piston will be retained, in anticipation of the nextstroke, whilst the steam on the upper` side will be exhausted. f

The steam or othcriluid is'then admitted for again raising the hammer.V

` When the steam or other fluid is to he admitted to the upper side of the piston, for accelerating the down ward stroke, the action ofthe-valves is as follows: i

ertain position, a communication is established between For this purpose 'the valves will he moved in a downward direction, admitting steam or other duid to the -under side o f the piston, and when the hammer has ascended suiiiciently high, the valves will be moved in the contrary direction, till the equilibrium-ports in the valves are opposite the ports in the casing, when the pressure in the cylinder will be equalized above and below the piston.

i This operation so far'is precisely the same as for the one previously described, or for the single-actinghammer, but instead ofy reversing the valves, as ih the previous case, they will continue moving in the saine direction, till the ports are open to the steam 4or other fluid at the top side of the piston, and to the exhanst-pipe on the bottom side. v

'The hammer will then descend with a velocitydue to its own gravity, and the pressure of the :steam or other iiuid on its top side.

After it has descended, the valve will be again moved downward, and the equilibrium-passage and ports opened, when a portionof the steam or other ni'd will pass from thetcp to the lower side of the piston, and will be retained there until the next charging, when the steam or other inid on thetop side will be exhausted. Instead of piston-valves, slide-valves, or conical or cylindrical valves may ber used, to the latter of which I give a. partial rotary motion, and provide the necessary passages for eiecting the object desired. n Two or more single valves may be adapted and applied to effect the same purposes as the valves referred to in the operation already described. v v y My improvements for effecting the object I have in vieware lillustrated in the accompanyingdraivings, in which- Figurel represents a Vertical section of a hammer-cylindeiwith piston, and with the valve-chest and valves' arranged to operateas heretofore described, the section being through the line'x :c of fig. 2.

Figure2 is a -horizontal section of fig. 1, through the line a a.

Figure 3 is a-horizontal section of g. 1, through the line B B. v

Figure 4 is a longitudinal Asection of the valve and chest, through the line c c of iig. 2.

Similar letters of reference indicate corresponding parts.

Referring again to g. 1, the steam or other luid is admitted into the valve-easing at a, (see Iig. 2,) and fills the annular space around the central portion bctwcen.tl1e pistons or valves efe, and it will be seen that -When the valves aremoved in a downward direction, the steam or other iuid will pass from theannular space b, through the port cZ to the under side of the piston, thereby raising the hammer which is attached to the rod e of the pistonf, and if when the hammer has ascended suihciently high, the mot-ion of the valves be reversed,

and brought to the position seen in the drawing, it will be seen that a communication is established between the' bottom and top of the cylinder, and a portion of the steam or other iuid will pass from thevunder side to the top of the piston, through the ports d and-g in the cylinder, by means of the equilibrium-ports in the valves.

H is the exhaust-pipe. I-is the valve-spindle, whichworks through a stuing-box, and is connected with belting or levers, or a self'- aeting motion in the ordinary manner. i

'Having thus described my invention, I claim as new, and desire to secure by Letters Patent@ The hollow piston-valve, provided at the'top and bolt/tom with the. valves c c, between whichl the annular space 5 is formed, arranged to operate in relation'with-the ports dg inA the cylinder, Athe induction-port a, and

exhaust H, as herein described for .the p uilpose specified.

The above specication of my inventionsigned by me, this second day of Decembexg'lS'GY.'

DAVID DAVY.

Witnesses:

ABRAHAM Davy, Junr., THos. TILLALLRN. 

